Electric-arc lamp.



ELECTRIC ARC LAMP.

(Application filed Oct. 25, 1898.)

(No Model.) 2 Sheets8heet l.

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No. 638,788. Patented Dec. l2, I899. E. WOLTMANN.

ELECTRIC ARC LAMP.

(Application filed Oct. 25; 1898.) (No Model.) 2 sheets-Sheet 2.

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UNITED STATES PATENT FFIoE.

ERNST WOLTMANN, OF NEW YORK, N. Y., ASSIGNOR OF ONE-HALF TO ALBERT ANDERSON AND JOHAN M. ANDERSEN, OF BOSTON, MASSA- CHUSETTS.

ELECTRlC-ARC LAMP.

SPECIFICATION forming part of Letters Patent N 0. 638,788, dated December 12 1899.

Application filed October 25, 1898. Serial No. 694,515. (No model.)

T0 all whom it may concern:

Be it known that I, ERNST WOLTMANN, a citizen of the United States, residing in New York, in the county of New York and State of New York, haveinvented an Improvement in Electric-Arc Lamps, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to electric-arc lamps, and is herein shown as embodied in an electric-arc lamp of the class known as the inclosed arc-lamp.

In arc-lamps as now commonly constructed and known to me the action of the mechanism for separating the carbons to establish the arc is too responsive-that is, the action upon the carbons when the current is turned on is so rapid as to suddenly separate the carbons such a distance as will break the arcbefore the carbons have had an opportunity to become sufiiciently heated to maintain the arc. As a result the current is interrupted until the carbons are again brought together to establish the circuit, whereupon they are again separated to establish the are. This action gives rise to what is comm only known as flickering of the lamp and is highly objectionable. The objectionable action referred to is more pronounced in alternating-current arc-lamps.

My present invention has for its object to overcome the above-mentioned objections and to provide an arc-lamp in which the carbons are separated by movement of its operating mechanism slower than the movement of the armature of the magnet which controls the movement of said mechanism. In accordance with this invention the means for separating the carbons is normally inactive and remains substantially inactive while the armature is being attracted to its magnet, but becomes fully active after the armature has been attracted and continues active until the arc has been fully established. These and other features of this invention will be pointed out in the claims at the end of this specification.

Figure 1 represents in elevation, with parts broken away, an electric-arc lamp embodying this invention; and Fig. 2, a detail, on an enlarged scale, to be referred to.

In the present instance I have shown one form of electric-arc lamp embodying my invention and which comprises a casin g or shell a, an outer globe 0., and an inner globe a within which the arc is established between a lower carbon (not shown) and an upper carbon a movable in a tube a connecting two disks or plates a a, attached to side bars a a and forming therewith the main portion of the lamp-frame. The carbon a in accordance with this invention is designed to be gradually raised to gradually establish and maintain the are. This result may and preferably will be accomplished with the construc tion herein shown and which will now be described.

The lamp-frame supports an electromagnet or solenoid, having, as shown, two spools b I), into which extend the cores 5 Z9 connected by a tie or cross bar I), the said cores and tiebar being hereinafter referred to as the armature of the electromagnet. The cross-bar b of the armature, as shown, is provided with an opening, through which extends a rod 1), connected at its upper end to the cylinder 1) of a dash-pot, which has its piston 11 and piston-rod b stationary, the latter being fastened to the disk a, as by nuts b The rod b is extended through an opening in the disk a and has its lower end pivotally connected to a clutch I), which may be of any suitable construction and which is shown as a ringincircling the carbon a v The armature is not positively connected to the rod Z) and is free to respond to the attraction of the magnet when the latter is energized without producing immediate sepa ration of the carbons, and with the construction herein shown the said armature becomes stationary and in its attracted position before the upper carbon is lifted out of contact with the lower carbon. The armature therefore merely serves to place in active condition an agent which is normally inactive and which effects the separation of the carbons. The

agent referred to may and preferably will be a spring 0, which encircles the rod b above the cross-bar of the armature and is normally distended, having one end resting on said cross-bar and the other end bearing against I a suitable stop carried by the rod Z) and shown as a washer c and pin 0 The spring 0 is compressed by the attraction of the armature being resisted by the dash-pot; but when the armature is in its attracted position it serves as a solid or stationary abutment, against which the compressed spring bears, and the strength of the spring in its compressed condition is sufficient to overcome the resistance of the dash-pot and the weight of the upper carbon, and consequently the spring bearing against the armature expands and moves the rod Z) upward for substantially the full range of movement of the upper carbon, thereby lifting the said upper carbon away from the lower carbon, and thus establishing the are of the desired or normal length.

The expansion of the springcis resisted in the present instance by the dash-pot and takes place slowly or at least in a gradual manner, which insures a gradual separation of the carbons, and therefore affords ample time for said carbons to become heated to such degree as will insure the are being maintained during the entire separation or full range of movement of the carbons, thereby avoiding the objectionable flickering of the lamp. The rod 1), as shown, is encircled below the crossbar b of the armature by a spiral spring d, which is shorter than the spring 0 and rests upon a washer (1, supported by a pin (1 The spring cl merely supports the armature in a yielding manner, and its function is to prevent vertical vibration of the armature being transmitted to the carbon (L3 through the rod 19".

The clutch I) in the present instance normally rests upon the metal cap (i for the innor globe (L The operation of the lamp may be briefly described as follows: \Vhen the lamp is cut out of circuit, the carbons are in contact, and when the current is turned 011 the magnet attracts its armature substantially in an instant, and during this movement of the armature the spring 0 is compressed. The movement of the armature being substantially instantaneous is so rapid that the carbons are not separated, or at most separated an inappreciable amount, and theseparating agent, which in the present instance is the spring 0, remains inactive, or practically so, during the movement of the armature toward its magnet. IrVhen the armature is in its attracted position, the spring 0 becomes active and moves the rod 1) upward, thereby slowly lifting the upper carbon from the lower carbon the full range of movement required or desired to establish the are of the desired or proper length. The action of the spring 0 upon the rod to lift the carbon may be controlled or regulated, as in the present instance, by the dash-pot, which retards the action of the spring, so as to insure a slow and steady separation of the carbons. When the magnet becomes weal:-

ened by the abnormal size of the arc, the armature descends and the rod 1) also descends su ffieiently to permit of the feed of the upper carbon to restore the arc to its normal size. The down movement of the armature is cushioned by the spring (Z, which acts to prevent excessive jumping or vibration of the armature.

I have herein shown and described the active agent as the spring (3, and while I prefer this construction I do not desire to limit myself in this respect, as the well-known equivalent of a springnamely, a weightmay be used instead thereof.

I claim- 1. In an electric-arc lamp, the combination of the following instrumentalities, viz: an electromagnet, an armature therefor, a clutch constructed to engage one of the lamp-carbons to liftthe same and to permit movement of the carbon through it while the lamp is in operation, a rod connected to said clutch and extended loosely through said armature, and means acting on said rod to lift the carbon, said means being substantially inactive upon the carbon while the armature is being attracted, and becoming fully active to move said carbon for substantially the entire range of its movement after said armature is in its attracted position, substantially as described.

2. In an electric-arc lamp, the combination of the following instrumentalities, viz: an electromagnet, an armature therefor, a clutch constructed to engage one of the lamp-carbons to lift the same and to permit the movement of the carbon through it while the lamp is in operation, a rod connected to said clutch and extended loosely through said armature, a spring interposed between said armature and a stop on the portion of said rod above said armature, and of a length sufficient to permit it to be compressed by the movement of the armature without effecting material movement of said rod, clutch and carbon, substantially as described.

In an electric-arc lamp, the combination of the following instrumentalities, viz: an electromagnet, an armature therefor, a clutch to engage one of the lamp-carbons to lift the same and to permit movement of the carbon through it while the lamp is in operation, a rod connected to said clutch and extended loosely through said armature,a substantially long spring interposed between said armature and a stop on the portion of said rod above said armature, and a second spring interposed between said armature and a stop on said rod below said armature, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ERNST WOLTMANN.

Witnesses:

Jas. II. CHURCHILL, J. MURPHY. 

